A fluid catalytic cracking (FCC) unit includes a variety of different components that work together to perform the process of cracking of heavy hydrocarbons into lighter hydrocarbons with a fluidized stream of catalyst particles. One example of an FCC unit is disclosed in U.S. Pat. No. 8,266,818, issued on Jul. 24, 2012, and which is hereby incorporated by reference in its entirety. Of course, many other FCC units are known, and could be utilized with the present invention. As known in the art, the reactor and the regenerator are two of the important components of an FCC unit. Two of the functions of the reactor are: (i) separating the cracked product vapors from the spent catalyst by running the vapor through one or more catalyst separation devices, such as cyclones, second stage separators or third stage separators within the reactor vessel; and (ii) removing hydrocarbon vapors from the spent catalyst after it has gone through the catalyst separation device(s), before returning the spent catalyst to a catalyst regenerator. In the regenerator, the catalyst is further separated and regenerated by burning coke from the catalyst.